Technological advancements in manufacturing have become essential as a seemingly endless array of consumer electronic devices continue to flood the commercial market. One of the most promising manufacturing improvements is with the introduction of surface mount technology using reflow furnaces and a conductive adhesive, typically solder. Surface mount technology is rapidly replacing through-hole assembly of printed circuit board because of speed of assembly and the ease of achieving a higher packing density.
Depending upon the application, the marketplace today is continually demanding smaller, faster, lighter or increased power in these consumer electronic devices. Surface mount technology permits components to be mounted on both sides of a printed circuit board, if required, thereby increasing the packing density, i.e., the number of components per unit of area of the printed circuit board.
The same demands of smaller, faster, lighter or increased power generally require electrical components with higher current capacities. This is especially true for magnetic devices such as transformers and inductors. However, the design of transformers and inductors is dictated by elemental electrical engineering principles regarding the number of required turns of a winding as dictated by the desired output. As winding layers are added to achieve the desired inductance or transformer ratio, the magnetic device increases in thickness and as a result the inductor footprint requires additional printed circuit board space. The additional winding turns and higher current generate more heat that needs to be dissipated. Also, the heat generated by high current capacity inductors increases with the square of the current.
In an attempt to compensate for the size of the additional windings, some prior art magnetic devices have employed smaller conductors that have been decreased in size in some proportion to the increased winding size. Such configurations invariably lead to higher losses from the windings, rendering such a configuration undesirable. These factors and others necessitate larger or additional heat sinks to cope with the increased heat, further affecting the space constraints associated with the printed circuit boards.
Accordingly, what is needed in the art is a surface mount magnetic device having properties that avoid the disadvantages of the prior art.